U.S. patent number 6,899,425 [Application Number 10/694,962] was granted by the patent office on 2005-05-31 for multifocal ophthalmic lenses.
This patent grant is currently assigned to Johnson & Johnson Vision Care, Inc.. Invention is credited to James W. Haywood, Larry G. Jones, Jeffrey H. Roffman.
United States Patent |
6,899,425 |
Roffman , et al. |
May 31, 2005 |
Multifocal ophthalmic lenses
Abstract
The invention provides multifocal lenses for correction of
presbyopia. Each of the lenses of the invention provide both
distance and near vision correction by providing both a first
multifocal region, a monofocal region, and a second multifocal
region within the same lens.
Inventors: |
Roffman; Jeffrey H.
(Jacksonville, FL), Jones; Larry G. (Jacksonville, FL),
Haywood; James W. (Orange Park, FL) |
Assignee: |
Johnson & Johnson Vision Care,
Inc. (Jacksonville, FL)
|
Family
ID: |
34522679 |
Appl.
No.: |
10/694,962 |
Filed: |
October 28, 2003 |
Current U.S.
Class: |
351/159.21;
623/6.29 |
Current CPC
Class: |
G02C
7/028 (20130101); G02C 7/042 (20130101); G02C
7/044 (20130101); G02C 7/045 (20130101) |
Current International
Class: |
G02C
7/04 (20060101); G02C 007/04 () |
Field of
Search: |
;351/159,160R,161,164,168-9,171-2,177
;623/6.11,6.3,6.19,6.24,6.27,6.29 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
US. Appl. No. 10/354,401, Jones et al. .
U.S. Appl. No. 10/357,873, Roffman et al. .
U.S. Appl. No. 10/284,613, Roffman et al..
|
Primary Examiner: Schwartz; Jordan M.
Assistant Examiner: Stultz; Jessica
Attorney, Agent or Firm: Gianneschi; Lois
Claims
What is claimed is:
1. A lens, comprising an optic zone having a first region that is a
multifocal region located at the optical center of a surface of the
lens, a second region that is a monofocal region located adjacent
to and encircling the multifocal region, and a third region of
alternating distance optical power segments and near optical power
segments located adjacent to and encircling the monofocal region
wherein the near optical power segments are asymmetrical.
2. The lens of claim 1, wherein the lens is a contact lens.
3. The lens of claim 2, wherein the first, second and third regions
are located on a front surface of the lens.
4. The lens of claim 2, wherein the lens further comprises a
cylinder power.
5. The lens of claim 3, wherein a back surface of the lens is a
toric surface.
6. The lens of claim 3, wherein a back surface of the lens
inversely corresponds to an individual's corneal topography.
7. A contact lens, comprising an optic zone having a first region
that is a multifocal region, a second region that is a monofocal
region, and a third region of alternating distance optical power
segments and near optical power segments wherein the near optical
power segments are asymmetrical wherein the first multifocal region
is designed so that a position, an amplitude, and a width for the
region is determined by the following equation: ##EQU2##
wherein: Y is an add power at any point x on a surface within the
multifocal region; x is a point on the lens surface; a is 0.5; k is
a point within the multifocal region at which there is a power
peak; P is greater than about 0 and less than about 15; S is
greater than about 0 and less than about 30; and Add is a value
that is equal to or less than a difference in power between the
near vision power and distance vision power of the multifocal
region.
8. A contact lens, comprising an optic zone having a first region
that is a multifocal region, a second region that is a monofocal
region, and a third region of alternating distance optical power
segments and near optical power segments wherein the near optical
power segments are asymmetrical, wherein the multifocal region is
designed so that a speed or contour, meaning, the slope of the
power change from near to distance power, for the zone is
determined by the following equation:
wherein: Add.sub.(x) is an actual instantaneous add power at any
point x in the multifocal region; x is a point in the multifocal
region at a distance x from a center of the surface; a is a
constant; Add.sub.peak is an add power required for near vision
correction; x.sub.c is a midpoint in a power transition from
distance to near power in the multifocal region; n is a variable
between 1 and 40; and Add is a value that is equal to the
difference the near vision power and distance vision power in the
multifocal region.
9. A contact lens, comprising an optic zone having a first region
that is a multifocal region, a second region that is a monofocal
region, and a third region of alternating distance optical power
segments and near optical power segments wherein the near optical
power segments are asymmetrical, wherein the multifocal region is
designed so that a speed or contour for the zone is determined by
the following equation:
wherein: Add.sub.(x) is actual instantaneous add power at any point
x on a surface of the lens within the multifocal region; x is a
point on the lens surface at a distance x from the center; a is a
constant and preferably is 1; Add.sub.peak is the full peak
dioptric add power within the multifocal region; x.sub.c is the
cutoff semi-diameter within the multifocal region; n is is a
variable between 1 and 40, preferably between 1 and 20; and Add is
a value that is equal to the difference in power between the near
vision power and distance vision power of the multifocal
region.
10. A contact lens, comprising an optic zone having a first region
that is a multifocal region, a second region that is a monofocal
region, and a third region of alternating distance optical power
segments and near optical power segments wherein the near optical
power segments are asymmetrical, wherein the multifocal region is
designed so that a speed and a contour for the region is determined
by the following equation:
wherein: Add.sub.(x) is actual instantaneous add power at any point
x on a surface of the lens within the multifocal region; x is a
point on the lens surface at a distance x from the center; a is a
constant and preferably is 1; d is an arbitrary value between 1 and
40; Add.sub.peak is the full peak dioptric add power within the
multifocal region; x.sub.c is the cutoff semi-diameter within the
multifocal region; n is between 1 and 40, preferably between 1 and
20; and Add is a value that is equal to the difference in power
between the near vision power and distance vision power of the
multifocal region.
11. A method of designing a lens, comprising the step of providing
an optic zone having a first region that is a multifocal region
located at the optical center of a surface of the lens, a second
region that is a monofocal region located adjacent to and
encircling the multifocal region, and a third region of alternating
distance optical power segments and near optical power segments
located adjacent to and encircling the monofocal region wherein the
near optical power segments are asymmetrical.
12. A method of correcting presbyopia, comprising the step of
providing an optic zone having a first region that is a multifocal
region located at the optical center of a surface of the lens, a
second region that is a monofocal region located adjacent to and
encircling the multifocal region, and a third region of alternating
distance optical power segments and near optical power segments
located adjacent to and encircling the monofocal region wherein the
near optical power segments are asymmetrical.
13. The lens of claim 1, wherein the monofocal region surrounds the
multifocal region and the third region surrounds the monofocal
region.
14. The lens of claim 1, wherein the segments of the third region
are radial segments.
15. The lens of claim 14, wherein the radial segments are
triangular in shape.
16. The lens of claim 13, wherein the segments of the third region
are radial segments.
17. The lens of claim 16, wherein the radial segments are
triangular in shape.
18. The lens of claim 7, wherein the segments of the third region
are radial segments.
19. The lens of claim 18, wherein the radial segments are
triangular in shape.
20. The lens of claim 8, wherein the segments of the third region
are radial segments.
21. The lens of claim 20, wherein the radial segments are
triangular in shape.
22. The lens of claim 9, wherein the segments of the third region
are radial segments.
23. The lens of claim 22, wherein the radial segments are
triangular in shape.
24. The lens of claim 10, wherein the segments of the third region
are radial segments.
25. The lens of claim 24, wherein the radial segments are
triangular in shape.
26. The lens of claim 7, wherein the monofocal region surrounds the
multifocal region and the third region surrounds the monofocal
region.
27. The lens of claim 8, wherein the monofocal region surrounds the
multifocal region and the third region surrounds the monofocal
region.
28. The lens of claim 9, wherein the monofocal region surrounds the
multifocal region and the third region surrounds the monofocal
region.
29. The lens of claim 10, wherein the monofocal region surrounds
the multifocal region and the third region surrounds the monofocal
region.
Description
FIELD OF THE INVENTION
The invention relates to ophthalmic lenses. In particular, the
invention provides lenses that incorporate more than one optical
power, or focal length, and that are useful in the correction of
presbyopia.
BACKGROUND OF THE INVENTION
As an individual ages, the eye is less able to accommodate, or bend
the natural lens, to focus on objects that are relatively near to
the observer. This condition is known as presbyopia. Similarly, for
persons who have had their natural lens removed and an intraocular
lens inserted as a replacement, the ability to accommodate is
totally absent.
Among the methods used to correct presbyopia is the mono-vision
lens system in which a person is fitted with, and wears, two
contact lenses; one lens for distance vision and one lens for near
vision. The mono-vision system permits the wearer to distinguish
both distance and near objects, but is disadvantageous in that a
substantial loss in depth perception results.
Another method for presbyopia correction is the use of multifocal
contact lenses. Each multifocal contact lens provides distance and
near vision power or distance, near and intermediate power. These
lenses overcome the depth perception loss and typically use
alternating concentric rings or alternating radial segments of
distance and near power. However, multifocal contact lenses are
problematic in that they expose the wearer's retina to two images
at once, one in and one out of focus. The two images are not
disadvantageous for near vision because the out of focus distance
objects being viewed in the near segments of the lens do not
interfere, but rather contribute to the near vision resolution. The
reason for this is that the out of focus distance objects are in an
orientation that does not interfere with the near images.
However, such lenses are problematic for distance vision. As the
wearer views distant objects through the lens, the near images also
being viewed go through focus before the distant images. As a
result, the out of focus near images are inverted and interfere
with the image of the distant object. Thus, a need exists for
multifocal lenses that that overcome the disadvantages of known
lenses.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a lens surface of one embodiment of the
lens of the invention.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
The invention provides methods for correcting presbyopia, lenses
for such correction, and methods for producing the lenses of the
invention. Each of the lenses of the invention provide both
distance and near vision correction by providing both multifocal
and monofocal regions within the same lens.
In one embodiment, the invention provides an ophthalmic lens for a
lens wearer comprising, consisting essentially of, and consisting
of an optic zone having a first region that is a multifocal region,
a second region that is a monofocal region, and a third region of
alternating distance optical power segments and near optical power
segments wherein the near optical power segments are
asymmetrical.
By "ophthalmic lens" is meant a contact, intraocular lens, or the
like, or combinations thereof. Preferably, the lenses of the
invention are contact lenses. By "multifocal region" is meant a
region in which the power continuously increases from distance to
near optical power or continuously decreases from near to distance
optical power as one moves outwardly toward the lens edge from the
center of the region.
By "distance optical power" is meant the amount of refractive power
required to correct the wearer's distance vision acuity to the
desired degree. By "near optical power" is meant the amount of
refractive power required to correct the wearer's near vision
acuity to the desired degree. By "asymmetrical" is meant that given
any first point that is on a near optical power segment of the lens
surface, any second point on the surface that is at a corresponding
location 180 degrees around the center of the lens from the first
point is a point on a distance optical power segment of the
surface. The near optical power segments in the asymmetrical
portion of the lenses of the invention may be any distance from
each other provided that the asymmetry requirement is met.
FIG. 1 depicts a plan view of a surface of lens 10 of the
invention. Lens 10 has an optic zone containing multifocal region
11, monofocal region 12, and region 15 which is a region of
asymmetric, alternating, distance and near optical power segments.
The optic zones is surrounded by non-optical zone 16. The
multifocal region of the lens of the invention preferably is
located at the optical center of a surface of the lens. The
multifocal region used in the lenses of the invention has at least
distance and near vision power, and preferably distance, near, and
intermediate vision power. By "intermediate vision power" is meant
power that is suitable for viewing objects located at distances of
about 46 to about 80 cm from the eye. Intermediate vision power may
be supplied as a consequence of the power progression between the
peak of the power of the near and distance optical power within the
multifocal zone. In a preferred embodiment, a pair of lenses
according to the invention is provided, the lens to be worn on the
eye dominant for distance vision having a multifocal region in
which the power continuously increases from distance to near
optical power as one moves outwardly from the center of the lens
and region to the periphery of the region.
The multifocal region may be designed by any convenient method.
Preferably, the multifocal region is designed wherein a position,
an amplitude, and a width for the region is determined by the
following equation: ##EQU1##
wherein: Y is the Add power at any point x on a surface within the
multifocal region; x is a point on the lens surface; a is 0.5; k is
the point within the multifocal region at which the power peaks; P
is the coefficient that controls the width of the multifocal region
and is greater than about 0 and less than about 15; S is the
coefficient that controls the amplitude and its decrease in the
periphery of the multifocal region and is greater than about 0 and
less than about 30; and Add is a value that is equal to or less
than the difference in power between the near vision power and
distance vision power of the multifocal region.
Alternatively, the multifocal region may be a region wherein a
speed or contour, meaning, the slope of the power change from near
to distance power, for the zone is determined by the following
equation:
wherein: Add.sub.(x) is actual instantaneous add power at any point
x on a surface of the lens within the multifocal region; x is a
point on the lens surface at a distance x from the center; a is a
constant and preferably is 1; Add.sub.peak is the full peak
dioptric add power, or add power required for near vision
correction; x.sub.c is the cutoff semi-diameter or the midpoint in
the power transition from distance to near power, or near to
distance power within the multifocal region; n is a variable
between 1 and 40, preferably between 1 and 20; and Add is a value
that is equal to the difference in power between the near vision
power and distance vision power of the multifocal region.
In Equation II, n is the variable that controls the slope of the
progression from near to distance vision power and distance to near
vision power in the multifocal region. The less the value of n, the
more gradual the progression will be.
In another embodiment, the multifocal power region may be such that
the a speed or contour for the zone is determined by the following
equation:
wherein: Add.sub.(x) is actual instantaneous add power at any point
x on a surface of the lens within the multifocal region; x is a
point on the lens surface at a distance x from the center; a is a
constant and preferably is 1; Add.sub.peak is the full peak
dioptric add power within the multifocal region; x.sub.c is the
cutoff semi-diameter within the multifocal region; n is is a
variable between 1 and 40, preferably between 1 and 20; and Add is
a value that is equal to the difference in power between the near
vision power and distance vision power of the multifocal
region.
In a fourth embodiment, the multifocal power region is such that
the speed and a contour for the region is determined by the
following equation:
wherein: Add.sub.(x) is actual instantaneous add power at any point
x on a surface of the lens within the multifocal region; x is a
point on the lens surface at a distance x from the center; a is a
constant and preferably is 1; d is an arbitrary value between 1 and
40; Add.sub.peak is the full peak dioptric add power within the
multifocal region; x.sub.c is the cutoff semi-diameter within the
multifocal region; n is between 1 and 40, preferably between 1 and
20; and Add is a value that is equal to the difference in power
between the near vision power and distance vision power of the
multifocal region.
The second region of the lens lies at the periphery, and preferably
surrounds, the multifocal region. The second region is a monofocal
region that may be distance, intermediate, or near optical power.
The power of the monofocal region preferably is the same power as
the power at the extreme periphery of the multifocal region and
which is immediately adjacent to the monofocal region. For example,
if the multifocal region increases from near to distance vision
power as one moves from the center of the multifocal region to the
its periphery, relative to the lens periphery, the monofocal region
will be distance vision power.
The third region of the lens is adjacent to and lies at the
periphery of, and preferably substantially surrounds, the monofocal
region. The third region contains both distance and near optical
power segments of any convenient shape that are asymmetrical.
Preferably, the segments are radial segments. More preferably, the
radial segments are triangular in shape. Any number of near and
distance segments may be used. Preferably however, the number of
near optical power segments are equal to or less than the areas for
distance optical segments within the third region. The region may
also include segments of intermediate vision optical power.
However, if intermediate vision power segments are provided, they
too preferably are asymmetrical in that, given any first point that
is on an intermediate optical power segment of the lens surface,
any second point on the surface that is at a corresponding location
180 degrees around the center of the lens from the first point is a
point on a distance or near optical power segment of the
surface.
As shown in FIG. 1 region 15 has near optical power segments 13
alternating with distance optical power segments 14. As shown, the
distance and near segments are arc-shaped alternating as one moves
circumferentially around the center of the lens. Any number of
alternating distance and near segments may be used. Preferably,
three segments each of distance and near optical power are
used.
In the lenses of the invention, the distance, near, and
intermediate optical powers may be spherical, aspheric, or toric
powers. Additionally, each of the three regions and the distance,
near optical power zones or segments therein may be of any desired
and practical dimensions. The multifocal, monofocal, and
asymmetrical distance and near segment regions may be on the same
surface of the lens. Alternatively, the multifocal and monofocal,
multifocal and asymmetrical segments, or asymmetrical segments and
monofocal region may be on one surface and the remaining region may
be on the opposite lens surface. Preferably, the multifocal,
monofocal, and asymmetric regions are all on the same surface. More
preferably, all three regions are on the front, or object side,
surface of the lens.
The lens of the invention may, if desired, include a zone for
rotationally stabilizing the lens on eye. Any number of rotational
stabilization zones are known in the art and may be used in the
lens of the invention. Typically, rotational stabilization is
categorized as static or dynamic stabilization. Examples of
rotational stabilization includes, without limitation, ballast,
prism ballast, thick zone, thin zone, protuberances on the lens
surface, such as one or more bosses, and the like and combinations
thereof. If the lens includes toric correction, or cylinder power,
a stabilization zone will be required.
In still another embodiment of the invention, one surface of the
lens provides each of the multifocal, monofocal and asymmetric
segment regions and the other surface of the lens corrects the lens
wearer's high order aberrations. By high order aberrations is meant
aberration of third or higher order. In yet another embodiment, on
the front surface of the lens is each of the multifocal, monofocal
and asymmetric segment regions and the back, or eye side, surface
is matched to the wearer's corneal topography meaning that the back
surface inversely corresponds to the wearer's corneal topography.
Such lens incorporates an inverse topographic elevation map of the
lens wearers' cornea. The inverse topographic elevation map may be
derived from the wearer's corneal topography, which corneal
topography may be determined by any known method including, without
limitation, by use of a corneal topographer. For soft contact lens
manufacture, the elevational data initially is applied to a lens
model in the unflexed state. Next, the data is transformed by
taking into account the soft lens flexure, or wrap, when the lens
placed on the eye. Thus, the effects of both elevation of the
cornea and wrap are accounted for when using the corneal
topographic data. The flexure transformed data then may be mapped
onto a CNC grid pattern and used to make the lenses or mold tool
surface.
In yet another embodiment, cylinder power may be provided. In one
such embodiment, on one surface of the lens is each of the
multifocal, monofocal and asymmetric a segment regions and the
opposite surface is a toric surface. As yet another embodiment,
cylinder power may be combined with one or more of the asymmetric
distance and near optical power segments, the monofocal, and the
multifocal region.
The lenses of the invention may be made by any convenient method.
One such method uses a lathe to produce mold inserts. The mold
inserts in turn are used to form molds. Subsequently, a suitable
lens material is placed between the molds followed by compression
and curing of the resin to form the lenses of the invention. One
ordinarily skilled in the art will recognize that any number of
known methods may be used to produce the lenses of the
invention.
Contact lenses useful in the invention may be made of hard lens
materials or soft lens materials, but the invention may provide
particular utility when applied to the design and production of
soft contact lenses. Thus, soft contact lenses, made of any
material suitable for producing such lenses, preferably are used.
Illustrative materials for formation of soft contact lenses
include, without limitation silicone elastomers,
silicone-containing macromers including, without limitation, those
disclosed in U.S. Pat. Nos. 5,371,147, 5,314,960, and 5,057,578
incorporated in their entireties herein by reference, hydrogels,
silicone-containing hydrogels, and the like and combinations
thereof. More preferably, the surface is a siloxane, or contains a
siloxane functionality, including, without limitation, polydimethyl
siloxane macromers, methacryloxypropyl polyalkyl siloxanes, and
mixtures thereof, silicone hydrogel, such as galyfilcon, or a
hydrogel, such as etafilcon A.
A preferred lens material is a poly 2-hydroxyethyl methacrylate
polymers, meaning, having a peak molecular weight between about
25,000 and about 80,000 and a polydispersity of less than about 1.5
to less than about 3.5 respectively and covalently bonded thereon,
at least one cross-linkable functional group. This material is
described in U.S. Ser. No. 60/363,630 incorporated herein in its
entirety by reference. Suitable materials for forming intraocular
lenses include, without limitation, polymethyl methacrylate,
hydroxyethyl methacrylate, inert clear plastics, silicone-based
polymers, and the like and combinations thereof.
Curing of the lens material may be carried out by any means known
including, without limitation, thermal, irradiation, chemical,
electromagnetic radiation curing and the like and combinations
thereof. Preferably, the lens is molded which molding is carried
out using ultraviolet light or using the full spectrum of visible
light. More specifically, the precise conditions suitable for
curing the lens material will depend on the material selected and
the lens to be formed.
Polymerization processes for ophthalmic lenses including, without
limitation, contact lenses are well known. Suitable processes are
disclosed in U.S. Pat. No. 5,540,410 incorporated herein in its
entirety by reference.
* * * * *